LOCATION YAWNING                 WA

Established Series
Rev. PHR/CAB/MPR
06/2011

YAWNING SERIES

The Yawning series consists of very deep, well drained soils formed in thin volcanic ash mantles overlying glacial drift and colluvium. Yawning soils are found on slopes of 0 to 65 percent on debris aprons, valley walls, and terraces of glaciated mountain landscapes. The mean annual precipitation is about 1,900 millimeters. The mean annual temperature is about 5 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, isotic Typic Haplocryods

TYPICAL PEDON: Yawning ashy sandy loam, located on a forested southwest facing valley wall with a slope of 65 percent and an elevation of 1350 meters. When described on August 28, 2006 the soil was slightly moist throughout. (Colors are for moist soil unless otherwise noted.)

Oi--0 to 2 cm; slightly decomposed plant material; few very fine to fine roots; abrupt smooth boundary.

Oa--2 to 8 cm; highly decomposed plant material; common very fine to coarse roots; common fine irregular pores; extremely acid (pH 4.0); abrupt wavy boundary.

E--8 to 14 cm; grayish brown (10YR 5/2) ashy sandy loam, light gray (10YR 7/2) dry; weak fine subangular blocky structure; loose, very friable, nonsticky, nonplastic; common very fine to fine roots and few medium roots; common fine irregular pores; 5 percent fine gravel; extremely acid (pH 4.1); abrupt irregular boundary.

Bs--14 to 32 cm; dark reddish brown (5YR 3/4) very gravelly ashy sandy loam, reddish brown (5YR 5/4) dry; weak fine subangular blocky structure; loose, very friable, nonsticky, nonplastic; common very fine to coarse roots; common fine to medium irregular pores; 10 percent fine gravel and 30 percent medium to coarse gravel; strongly acid (pH 5.3); clear irregular boundary.

2BC--32 to 50 cm; dark yellowish brown (10YR 4/4) extremely cobbly sandy loam, light yellowish brown (10YR 6/4) dry; weak fine subangular blocky structure; loose, very friable, nonsticky, nonplastic; few very fine to fine roots and common medium to coarse roots; common medium interstitial pores; 10 percent fine gravel, 30 percent medium to coarse gravel, and 40 percent cobbles; strongly acid (pH 5.5); gradual irregular boundary.

2C1--50 to 100 cm; dark yellowish brown (10YR 4/6) extremely cobbly sandy loam, brownish yellow (10YR 6/6) dry; single grain; loose, nonsticky, nonplastic; few very fine to coarse roots; many coarse interstitial pores; 10 percent fine gravel, 25 percent medium to coarse gravel, 30 percent cobbles, and 20 percent stones; strongly acid (pH 5.5); gradual irregular boundary.

2C2--100 to 150 cm; dark yellowish brown (10YR 4/6) extremely cobbly sandy loam, brownish yellow (10YR 6/6) dry; single grain; loose, nonsticky, nonplastic; few fine to medium roots; many coarse interstitial pores; 10 percent fine gravel, 25 percent medium to coarse gravel, 30 percent cobbles, and 20 percent stones; strongly acid (pH 5.5).

TYPE LOCATION: Whatcom County, Washington; approximately 27 km northwest of the town of Newhalem along Easy Ridge, North Cascades National Park Service Complex; 785 meters west and 675 meters north of the southeast corner of Section 12, T. 39 N., R. 10 E. Willamette Meridian; Copper Mountain, Washington USGS quadrangle; 48 degrees 52 minutes 53 seconds north latitude and 121 degrees 26 minute 38 seconds west longitude; NAD83; UTM 614090 meters E, 5415030 meters N, zone 10N.

RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 4 to 8 degrees C.
Moisture control section - dry less than 30 consecutive days
Thickness of volcanic ash mantle - less than 25 centimeters
Particle size control section:
Clay content - 2 to 13 percent
Rock fragments - 35 to 85 percent

Total thickness of all organic horizons ranges from 3 to 15 centimeters.
Oe horizons exist in some pedons and range from 3 to 13 centimeters in thickness.

E horizon
Hue - 10YR or 7.5YR
Value - 3 to 5 moist, 5 to 7 dry
Chroma - 1 to 2 moist or dry
Fine earth texture - ashy SL or ashy FSL
Rock fragments - 0 to 15 percent fine to coarse gravel
Clay content - 1 to 8 percent
Volcanic glass - 5 to 50 percent
Reaction - extremely acid to very strongly acid
Thickness - 4 to 13 centimeters

Bs horizon
Hue - 5YR, 7.5YR or 10YR
Value - 2 to 4 moist, 4 to 5 dry
Chroma - 2 or 4 moist, 2 to 6 dry
Fine earth texture - ashy SL, ashy FSL or ashy L
Rock fragments - 15 to 75 percent total, 15 to 50 percent fine to coarse gravel, 0 to 20 percent cobbles, 0 to 5 percent stones
Clay content - 2 to 13 percent
Volcanic glass - 25 to 60 percent
Reaction - very strongly acid to strongly acid
Thickness - 11 to 20 centimeters

2BC horizon
Hue - 10YR or 2.5Y
Value - 3 to 5 moist, 5 to 7 dry
Chroma - 3 or 6 moist or dry
Fine earth texture - SL or COSL
Rock fragments - 35 to 80 percent total, 15 to 50 percent fine to coarse gravel, 5 to 40 percent cobbles, 0 to 5 percent stones
Clay content - 2 to 4 percent
Reaction - strongly acid to moderately acid
Thickness - 18 to 44 centimeters

2C horizons
Hue - 10YR or 2.5Y
Value - 3 to 5 moist, 5 to 7 dry
Chroma - 4 to 6 moist or dry
Fine earth texture - SL, COSL, or COS
Rock fragments - 35 to 85 percent total, 15 to 55 percent fine to coarse gravel, 0 to 30 percent cobbles, 0 to 20 percent stones
Clay content - 0 to 6 percent
Reaction - strongly acid to slightly acid

COMPETING SERIES: These are the Dinzer, Lastance, Mt. Hood and Ypsilon series. Dinzer and Lastance soils are deep (100 to 150 centimeters) to a lithic contact and lack andic soil properties. Mt. Hood soils are formed from glacial till derived from porphyritic andesitic and basaltic rocks. Ypsilon soils are somewhat excessively drained, lack andic soil properties and range in elevation from 2950 to 3350 meters.

GEOGRAPHIC SETTING: Yawning soils are found on slopes of 0 to 65 percent on valley walls, debris aprons, and terraces of glaciated mountain landscapes at elevations from 700 to 1,350 meters. They formed in volcanic ash overlying glacial drift and colluvium from glacial drift. The climate is characterized by cool, dry summers and cold, wet winters. Mean annual precipitation ranges from 1,450 to 2,200 millimeters and mean annual air temperature ranges from 3 to 7 degrees C. Frost free season is 30 to 60 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Chilliwack, Spickard and Tepeh soils. Chilliwack soils are medial over sandy or sandy-skeletal and have a mantle of andic soil materials 25 to 35 cm thick. Spickard soils are ashy over sandy or sandy-skeletal and lack albic and spodic horizon morphology. Chilliwack and Spickard soils are typically found on more stable and lower slope gradient landscape positions. Tepeh soils are found on more active landscape positions, have a mantle of andic soil materials 25 to 35 cm thick, and lack albic and spodic horizon morphology.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; high to very high saturated hydraulic conductivity.

USE AND VEGETATION: Yawning soils are used for wildlife habitat, recreation, and watershed. Native vegetation consists of Pacific silver fir and western hemlock with an understory of black huckleberry, five-leaf bramble and queenscup beadlilly.

DISTRIBUTION AND EXTENT: North Cascade Mountains, Washington. MLRA 3. Series is of small extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon

SERIES ESTABLISHED: North Cascades National Park Service Complex, Whatcom County, Washington, 2011.

REMARKS: Diagnostic horizons and features recognized in this pedon include:
Cryic soil temperature regime
Udic soil moisture regime
Particle-size control section - 33 to 108 centimeters
Ochric epipedon
Albic horizon - 8 to 14 centimeters (E horizon)
Spodic horizon - 14 to 32 centimeters (Bs horizon)
Andic soil properties - 8 to 32 centimeters (E and Bs horizons)
Lithologic Discontinuity - 32 centimeters

ADDITIONAL DATA: Laboratory data is available for this series. National Soil Survey Laboratory Pedon number 08NO316 (User pedon ID S08WA007004).

---

National Cooperative Soil Survey
U.S.A.